DouKaku?

#runtime "hsp3cl"
#module
#defcfunc spaces int len
    if len <= 0 : return ""

    sdim s, len + 1
    repeat len
        poke s, cnt, ' '
    loop
    return s

#defcfunc centered_text str target, int len
    if len <= 0 : return ""

    target_length = strlen(target)
    result = target
    if target_length < len {
        result = spaces((len - target_length)/2) + target + spaces((len - target_length + 1)/2)
    } else : if target_length > len {
        result = strmid(result, (target_length - len)/2, len)
    }
    return result
#global

    s = "*"
    repeat 10
        mes centered_text(s, 15)
        s += " *"
    loop
    stop